For example, there are air conditioning systems of a first type in which an air conditioner is remote-monitored and remote-controlled by communication from a central control unit and of a second type in which an air conditioner operates singly. The air conditioners are of a first type which has a predetermined part, for example, an electronic expansion valve of an indoor unit and of a second type which does not have an electronic expansion valve.
For example, the air conditioning system of the first type employs the air conditioner of the first type, and the air conditioning system of the second type employs the air conditioner of the second type.
The air conditioner of the first type requires a communication function for performing communication with the outside for the purpose of performing communication with a central control unit. On the other hand, the air conditioner of the second type does not require the communication function since communication with the outside is unnecessary.
In a conventional air conditioner, two controllers one of which has the communication function and the other of which has no communication function according to the first and second types have to be designed and manufactured. Generally, however, in order to reduce the cost by mass production, increase in price due to designing and manufacturing of a plurality of kinds of products exerts a larger influence on price than increase in price caused by addition of a function.
FIGS. 13 and 14 are block diagrams showing a conventional technique and illustrate the configurations of air conditioners of the second type and the first type, respectively. An air conditioner 100a shown in FIG. 13 includes an electronic circuit 21 customarily called a P board and a driving system 30a for performing compression of a refrigerant, heat exchange and the like. An air conditioner 100b shown in FIG. 14 includes the electronic circuit 21 and a driving system 30b. The driving system 30b includes, different from the driving system 30a, an electronic expansion valve EV.
The electronic circuit 21 has a control unit 5 and an integrated circuit 11 for giving an instruction to the control unit 5. In order to control each of the driving system 30a without electronic expansion valve EV and the driving system 30b with the electronic expansion valve EV, the control unit 5 and the integrated circuit 11 having the same configuration are used. Specifically, the control unit 5 directly controls each of the driving systems 30a and 30b, and the integrated circuit 11 indirectly controls each of the driving systems 30a and 30b. 
Generally, in a technique of controlling the operation of an equipment by a microcomputer, a CPU (Central Processing Unit) performs the control on the basis of predetermined data (including a program in the specification). The data is written in a ROM (Read Only Memory) and the CPU controls the operation of the equipment by using necessary data in the ROM. However, even when the kinds of models to be controlled are different from each other, an agent of the control can be easily designed and manufactured by employing the same configuration for the agent of the control.
The integrated circuit 11 has a rewritable EEPROM (Electrically Erasable Programmable ROM) 2 and a CPU 3. The CPU 3 gives the above instruction to the control unit 5. The instruction to the air conditioner 100a and the instruction to the air conditioner 100b are naturally different from each other depending on the presence/absence of the electronic expansion valve EV. Therefore, the initial value of data (referred to as “initial data” in the specification) based on which the CPU 3 operates in the case where the electronic circuit 21 is mounted on the air conditioner 100a and that in the case where the electronic circuit 21 is mounted on the air conditioner 100b are different from each other.
However, by properly selecting two different pieces of data to be stored as the initial data into the EEPROM 2 to store the selected data in the EEPROM 2 in accordance with the case where the electronic circuit 21 is mounted on the air conditioner 100a and the case where the electronic circuit 21 is mounted on the air conditioner 100b, the same configuration can be used for the electronic circuit 21 in both of the cases.
It is desirable to store the data based on which the CPU 3 operates in not the ROM but the EEPROM 2 also from the viewpoint of storing settings desired by the user as the air conditioners 100a and 100b are used.
In the conventional technique, however, which one of the air conditioners 100a and 100b is used is determined by a person and initial data of the EEPROM 2 is written accordingly from an external equipment by communication. It requires much efforts at the time of initial setting of the electronic circuit 21 or the air conditioners 100a and 100b each having the electronic circuit 21.
It is difficult to use the electronic circuit 21 which is once assembled in the air conditioner 100a or 100b and includes the EEPROM 2 into which initial data EEA or EEB is written as a patch part for the other air conditioner 100b or 100a. 